1. Technical Field of the Invention
The present invention relates to novel cosmetic compositions for topical application, for photoprotecting the skin and/or the hair against the deleterious effects of ultraviolet radiation (such compositions hereinbelow more simply referred to as antisun or sunscreen compositions), and to the use of same for the cosmetic applications indicated above.
This invention more especially relates to the aforesaid sunscreen/cosmetic compositions comprising, formulated into a cosmetically acceptable support (vehicle, diluent or carrier), admixture of (a) a benzotriazole compound first screening agent and (b) a specific bis-resorcinyltriazine compound second screening agent.
2. Description of the Prior Art
It is known to this art that light radiation with wavelengths of from 280 nm to 400 nm promotes tanning of the human epidermis, and that irradiation with wavelengths of from 280 nm to 320 nm, i.e., UV-B radiation, causes skin burns and erythema which may be harmful to the development of a natural tan; this UV-B radiation should thus be screened from the skin.
It is also known to this art that UV-A radiation, with wavelengths of from 320 nm to 400 nm, which causes tanning of the skin, can also induce an adverse change therein, especially in the case of sensitive skin or of skin which is continually exposed to solar radiation. UV-A rays cause, in particular, a loss of elasticity of the skin and the appearance of wrinkles, leading to premature skin aging. Such irradiation promotes triggering of the erythemal reaction or amplifies this reaction in certain individuals and may even be the cause of phototoxic or photoallergic reactions. It is thus desirable to also screen out UV-A radiation.
A wide variety of cosmetic compositions for the photoprotection (UV-A and/or UV-B) of human skin are known to this art.
These antisun/sunscreen compositions are quite often in the form of an emulsion of oil-in-water type (namely, a cosmetically acceptable vehicle comprising a continuous aqueous dispersing phase and a discontinuous oily dispersed phase) which contains, in various concentrations, one or more conventional lipophilic and/or hydrophilic organic screening agents which are capable of selectively absorbing harmful UV radiation. These screening agents (and their amounts) are selected as a function of the desired sun protection factor (the sun protection factor (SPF) which is expressed mathematically by the ratio of the irradiation time necessary to attain the erythemogenic threshold with the UV screening agent to the time necessary to attain the erythemogenic threshold without UV screening agent).
EP-B-0,742,003 describes antisun/cosmetic compositions having high sun protection factors; these compositions comprise a combination of two sunscreens, namely, (a) benzene-1,4-bis(3-methylidene-10-camphorsulfonic acid), optionally in partially or totally neutralized form, as a first screening agent, and (b), as a second screening agent, a benzotriazole silicone such as those described in EP-B-0,660,701. However, these sunscreen/photoprotecting products are usually considered to possess insufficient water remanence.